Unit 2

This section discusses the overall look and construction of the Java application. Most Java programs are composed of the same building blocks formatted in the same way from program to program. Read this section and be sure to try the simple program examples.

This section introduces variables, data types, literals (constant data values) and strings (groups of characters). The section ends with a discussion on how to best use variables in a program, and it concludes with an example you should try for yourself.

Read and review this section carefully.

• 2.2.1 Variables
• 2.2.2 Types
• 2.2.3 Literals
• 2.2.4 Strings and String Literals
• 2.2.5 Variables in Programs

This section begins with a discussion of some of the built-in functions you can call from within your own programs and includes an example you should try. The section then introduces classes and objects, and it discusses operations you can perform on strings. The section concludes with a discussion of the enumerated type (enum). Again, try the examples in this section.

Read and review this section carefully.

• 2.3.1 Built-in Subroutines and Functions
• 2.3.2 Classes and Objects
• 2.3.3 Operations on Strings
• 2.3.4 Introduction to Enums

This section begins by discussing and demonstrating a classic Java print statement (System.out.println) and how it can be used to display output from your program. Subsections 2.4.2 through 2.4.5 discuss the textbook author’s own input–output (I/O) class called TextIO. Read these subsections to get a sense of what the author is trying to accomplish; however, you will not be asked to use the class in your programs. The final part of this section discusses a more conventional Java input mechanism, Scanner. We will be using Scanner in programs for this course. Therefore, try the example in this section.

Read and review subsections 2.4.1 and 2.4.6 carefully.

• 2.4.1 Basic Output and Formatted Output
• 2.4.2 A First Text Input Example
• 2.4.3 Basic TextIO Input Functions
• 2.4.4 Introduction to File I/O
• 2.4.5 Other TextIO Features
• 2.4.6 Using Scanner for Input

This section discusses expressions, which are the basic building blocks of Java code, Java methods (subroutines), Java classes and objects and, ultimately, Java programs. The section discusses various operators that act on constants or variables to create expressions. Operators can be unary (acting on one thing) or binary (acting on two things). Operators can work with numbers or logic conditions. Assignment operators are used to assign the results of expressions to variables. Ultimately, there are rules that govern how operators are used, as well as which operations take precedence over (i.e., come before) other operations.

Read and review this section carefully.

• 2.5.1 Arithmetic Operators
• 2.5.2 Increment and Decrement
• 2.5.3 Relational Operators
• 2.5.4 Boolean Operators
• 2.5.5 Conditional Operator
• 2.5.6 Assignment Operators and Type Conversion
• 2.5.7 Precedence Rules

This last section of the chapter discusses programming environments. Subsection 2.6.1 discusses the essential Java environment, the Java Development Kit (JDK). All other Java environments employ the JDK to read and compile code. Some environments include the JDK, while others require you to download and install the JDK yourself. In this course, you will primarily use a standard Java SDK for exploring the Java concepts covered in this course. The environment you choose to use will depend on the computer operating system you have. The SDK can be installed and used on Windows, Unix, OSX (Macintosh) and Linux. All operating systems offer a form of “command shell” that can be used for compiling and executing Java programs.  We will not be using or covering Eclipse, NetBeans or BlueJ in this course, but you may choose to use NetBeans rather than the command line environment for your course study and assignments.

For now you can skip subsections 2.6.3 through 2.6.8. However, when you are ready to start Assignment 4 you may wish to read the subsections on Eclipse and other programming environments.

Subsection 2.6.7 discusses packages and Java. We will use packages in Assignment 4.

Read and review subsections 2.6.1, 2.6.2 and 2.6.7 carefully.

• 2.6.1 Getting JDK and JavaFX
• 2.6.2 Command Line Environment
• 2.6.3 JavaFX on the Command Line
• 2.6.4 Eclipse IDE
• 2.6.5 Using JavaFX in Eclipse
• 2.6.6 BlueJ
• 2.6.7 The Problem of Packages
• 2.6.8 About jshell

It is a good practice to attempt the programming exercises in the textbook, to put the topics you have learned into concrete Java code. This, in turn, allows you to reflect on the material you have read. Skip any exercises relating to topics in Chapter 2 that are not covered in the course.

It is a good practice to review the chapter quizzes in the textbook, as the questions allow you to reflect on the material you have read.